Various mesoscopic devices exploit electrostatic side gates for their operation. In this letter, we investigate how voltage biasing of graphene side gates modulates the electrical transport characteristics of a graphene channel. We explore myriads of typical side-gated devices such as symmetric dual-side gates and asymmetric single-side gates, in monolayer and bilayer graphene. The side gates modulate the electrostatic doping in the graphene channel whose effect is reflected in transport measurement. This modulation efficiency is systematically characterized for all our devices and agrees well with the modeling presented. © 2012 IEEE.